WASHINGTON - New geothermal power in the United States could double U.S. geothermal capacity.

The estimate comes from a Geothermal Energy Association survey, Environmental News Service reported.

Those projects that are in the pipeline will provide up to 3,368 megawatts of new electric capacity once they're developed. That is estimated to be enough to meet the needs of 6 million households.

Geothermal power is energy generated by heat stored beneath the Earth's surface. New projects are under way in Alaska, Arizona, California, Hawaii, Idaho, New Mexico, Nevada, Oregon, Texas, Utah, Washington and Wyoming, the association says.

U.S. Geothermal Inc. achieved commercial operation last week at its new geothermal power plant in Raft River, Idaho, making it the first commercial geothermal power plant in the state.

"The surge in new geothermal power development continues in the U.S.," said Karl Gawell, GEA's executive director.

According to the report, there are 86 new geothermal power projects currently under way in 12 states.

"If we can build and sustain this momentum, geothermal energy can become a major U.S. energy source," said Gawell. "But Congress and the administration must work together to extend the renewable energy tax credits before they expire."